1. Field of the Invention
The present invention pertains to a method of achieving zonal isolation in open-hole type completions by using a bypass to transport a consolidation material such as cement, or any other sealing material (for example a resin used for sand control and fluid shutoff), to the localized zones to be consolidated. Preferably these zones will be near the end connections of the pipe.
2. The Prior Art
From a production point of view, the most desirable method of completing either a vertical or horizontal well, especially in very competent formations, is to have an "open hole" well, i.e., a well that does not require cementing a casing or liner extending through the production zone. In general terminology, "open hole" can mean any well completion without any tubulars, or with a slotted liner, preperforated liner etc, with or without a gravel pack. However, open hole completions are often not used because of the difficulty encountered when trying to "work over" the completion. The work over could be required because of sand production, near wellbore damage, the need to fracture or acidize the well, or any of several other operations. Most of these operations require that certain zones within the production interval be treated individually. This is not normally possible in long open hole completions because it may be necessary to isolate small sections of the production zone, to ensure that the whole interval can be effectively treated. This is especially true for horizontal wells with long sections.
Numerous techniques have been attempted to achieve zonal isolation, but at the present time they are generally prohibitively expensive and notoriously unreliable. Diverting agents and pills are often used, but they are difficult to remove and may damage the zones of highest productivity. External inflatable packers may be used, but they are very expensive. In addition, inflatable packers have a very large percentage of failures.